Rotation sensor device and method of manufacturing the same including a doubled up mounting bracket for electrical contact

Abstract

A rotation sensor device capable of detecting rotation speed of a rotatable magnetic member with high accuracy and reliability even in a low rotation speed range and a method of manufacturing the same through simplified process. As a means for detecting a rotation frequency of a toothed-wheel-like rotatable magnetic member (100), a permanent magnet (25) and a magneto-electric conversion element (22) are used. Conductors (24) having these elements (22; 25) mounted at a tip end portion is embedded integrally in a base (23) of a resin material through an insert molding process such that the elements (22; 25) and those portions of the conductors which constitute mounting electrodes are exposed at least partially on the surface of the base (23). Electronic parts (26) are packaged on the mounting electrode portions (24a).

What is claimed is: 
     
       1. A rotation sensor device for detecting a rotational state of a rotatable magnetic member, comprising: a magneto-electric conversion element for detecting change of magnetic flux which takes place as said rotatable magnetic member rotates;   a base made of a resin material for holding at least said magneto-electric conversion element;   a base made of a resin material for holding at least said magneto-electric conversion element;   insert conductors embedded integrally in said base using an insert molding process, said insert conductors being partially exposed on a surface of said base, said magneto-electric conversion element being electrically connected to said insert conductors;   exposed mounting electrodes each formed by bending corresponding ones of said exposed portions of said insert conductors in a doubled-up structure, such that a respective mounting surface of the doubled-up structure of each of said exposed mounting electrodes lies along the surface of said base;   at least one electronic part being mounted on at least one of said exposed mounting electrodes and being electrically connected to said magneto-electric conversion element; and   a connector portion having terminal electrodes formed by end portions of said insert conductors.   
     
     
       2. A rotation sensor device according to claim 1, wherein said magneto-electric conversion element is comprised of a Hall element. 
     
     
       3. A rotation sensor device according to claim 1, wherein said magneto-electric conversion element is comprised of a magneto-resistance element. 
     
     
       4. A rotation sensor device according to claim 1, wherein said electronic part is comprised of a noise elimination filter circuit and a signal shaping circuit for shaping an output signal of said magneto-electric conversion element into a pulse signal. 
     
     
       5. A rotation sensor device according to claim 1, wherein said rotatable magnetic member is implemented in the form of a toothed wheel. 
     
     
       6. A rotation sensor device according to claim 1, further comprising: a permanent magnet interposed in a magnetic path of said rotatable magnetic member and said magneto-electric conversion element for completing a magnetic circuit, wherein said magneto-electric conversion element is bonded to a top surface of said permanent magnet by a bonding agent interposed between said permanent magnet and said magneto-electric conversion element.   
     
     
       7. A rotation sensor device according to claim 6, wherein said bonding agent is made of a composition capable of exhibiting resiliency even after said bonding agent has been hardened. 
     
     
       8. A rotation sensor device according to claim 1, wherein said permanent magnet is embedded in said base using an insert molding process with the top surface of said permanent magnet being exposed on the surface of said base. 
     
     
       9. An apparatus for measuring a rotational speed of a rotatable member, comprising: a toothed magnetic disk fixedly mounted on said rotatable member;   a rotation sensor device disposed in opposition to said toothed magnetic disk mounted on said rotatable member;   shaping circuit means connected to the output of said rotation sensor device for shaping an output signal of said rotation sensor device to thereby generate a pulse signal; and   arithmetic means for determining the rotational speed of said rotatable member on the basis of said pulse signal;   wherein said rotation sensor device comprises: a magneto-electric conversion element for detecting change of magnetic flux which takes place as said toothed magnetic disk rotates;   a base made of a resin material for holding said magneto-electric conversion element;   insert conductors embedded in said base using an insert molding process, said insert conductors being partially exposed on a surface of said base, said magneto-electric conversion element being electrically connected to said insert conductors;   exposed mounting electrodes formed by bending said exposed portions of said insert conductors in a doubled-up structure, such that a respective mounting surface of the doubled-up structure of each of said exposed mounting electrodes lies along the surface of said base;   at least one electronic part mounted on at least one of said exposed mounting electrodes, said at least one electronic part being electrically connected to said magneto-electric conversion element; and   a connector portion having terminal electrodes formed by end portions of said insert conductors.     
     
     
       10. A method of manufacturing a rotation sensor device for detecting a rotational state of a rotatable magnetic member, comprising the steps of: forming an insert conductor strip having individual insert conductors interconnected by joint portions in a predetermined pattern using a press working;   forming exposed mounting electrode portions by bending predetermined portions of said insert conductors in a doubled-up structure;   embedding said insert conductor strip in a base made of a resin material using an insert molding process, such that a respective mounting surface of the doubled-up structure of each of said exposed mounting electrode portions is located along the surface of said base;   cutting away unnecessary ones of said joint portions;   forming an electric connection by connecting a magneto-electric conversion element to said insert conductors;   mounting electronic parts on said exposed mounting electrodes of said insert conductors at predetermined locations; and   accommodating said base in a casing and thermally staking an open end portion of said casing to thereby secure said base and said casing to each other.   
     
     
       11. A method of manufacturing a rotation sensor device according to claim 10, wherein upon forming said base from a resin material using an insert molding process, recesses are formed at locations corresponding to said joint portions of said insert conductor strip, and wherein after embedding said insert conductor strip in said base through said insert molding process, unnecessary joint portions of said insert conductor strip are cut away by inserting a tool through said apertures. 
     
     
       12. A method of manufacturing a rotation sensor device according to claim 11, wherein recesses are formed in said base at positions corresponding to said exposed mounting electrode portions. 
     
     
       13. A method of manufacturing a rotation sensor device according to claim 10, wherein said electronic parts are mounted and secured onto said exposed mounting electrodes using a reflow soldering process.